selinux: add AF_UNSPEC and INADDR_ANY checks to selinux_socket_bind()

Commit d452930fd3b9 ("selinux: Add SCTP support") breaks compatibility
with the old programs that can pass sockaddr_in structure with AF_UNSPEC
and INADDR_ANY to bind(). As a result, bind() returns EAFNOSUPPORT error.
This was found with LTP/asapi_01 test.

Similar to commit 29c486df6a20 ("net: ipv4: relax AF_INET check in
bind()"), which relaxed AF_INET check for compatibility, add AF_UNSPEC
case to AF_INET and make sure that the address is INADDR_ANY.

Fixes: d452930fd3b9 ("selinux: Add SCTP support")
Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

1 files changed, 19 insertions, 10 deletions

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 21b377aef69a..16df6cca9a1b 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4568,6 +4568,7 @@ static int selinux_socket_post_create(struct socket *sock, int family,
 static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, int addrlen)
 {
         struct sock *sk = sock->sk;
+        struct sk_security_struct *sksec = sk->sk_security;
         u16 family;
         int err;
 
@@ -4579,11 +4580,11 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in
         family = sk->sk_family;
         if (family == PF_INET || family == PF_INET6) {
                 char *addrp;
-                struct sk_security_struct *sksec = sk->sk_security;
                 struct common_audit_data ad;
                 struct lsm_network_audit net = {0,};
                 struct sockaddr_in *addr4 = NULL;
                 struct sockaddr_in6 *addr6 = NULL;
+                u16 family_sa = address->sa_family;
                 unsigned short snum;
                 u32 sid, node_perm;
 
@@ -4593,11 +4594,20 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in
                  * need to check address->sa_family as it is possible to have
                  * sk->sk_family = PF_INET6 with addr->sa_family = AF_INET.
                  */
-                switch (address->sa_family) {
+                switch (family_sa) {
+                case AF_UNSPEC:
                 case AF_INET:
                         if (addrlen < sizeof(struct sockaddr_in))
                                 return -EINVAL;
                         addr4 = (struct sockaddr_in *)address;
+                        if (family_sa == AF_UNSPEC) {
+                                /* see __inet_bind(), we only want to allow
+                                 * AF_UNSPEC if the address is INADDR_ANY
+                                 */
+                                if (addr4->sin_addr.s_addr != htonl(INADDR_ANY))
+                                        goto err_af;
+                                family_sa = AF_INET;
+                        }
                         snum = ntohs(addr4->sin_port);
                         addrp = (char *)&addr4->sin_addr.s_addr;
                         break;
@@ -4609,13 +4619,7 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in
                         addrp = (char *)&addr6->sin6_addr.s6_addr;
                         break;
                 default:
-                        /* Note that SCTP services expect -EINVAL, whereas
-                         * others expect -EAFNOSUPPORT.
-                         */
-                        if (sksec->sclass == SECCLASS_SCTP_SOCKET)
-                                return -EINVAL;
-                        else
-                                return -EAFNOSUPPORT;
+                        goto err_af;
                 }
 
                 if (snum) {
@@ -4673,7 +4677,7 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in
                 ad.u.net->sport = htons(snum);
                 ad.u.net->family = family;
 
-                if (address->sa_family == AF_INET)
+                if (family_sa == AF_INET)
                         ad.u.net->v4info.saddr = addr4->sin_addr.s_addr;
                 else
                         ad.u.net->v6info.saddr = addr6->sin6_addr;
@@ -4686,6 +4690,11 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in
         }
 out:
         return err;
+err_af:
+        /* Note that SCTP services expect -EINVAL, others -EAFNOSUPPORT. */
+        if (sksec->sclass == SECCLASS_SCTP_SOCKET)
+                return -EINVAL;
+        return -EAFNOSUPPORT;
 }
 
 /* This supports connect(2) and SCTP connect services such as sctp_connectx(3)